You are given a `2.18g` sample containing a mixture of XO and `X_2O_3`. It takes 0.015 " mol of "`K_2Cr_2O_7` to oxdise the sample completely to form `XO_4^(ɵ)` and `Cr^(3+)`. If 0.0187 " mol of "`XO_4^(ɵ)` is formed, what is the atomic mass of X?

Explanation

Applying POAC for X atoms of atomic mass say x ,
mole of `XO+2 xx` mole of `X_(2)O_(3) ` mole of `XO_(4)^(-)`
`m/(x+16) +(2(2.198 -m))/(2x+48) = 0.0187 " "…(1)`
Applying law of equivalence ,
eq. of XO + eq. of `X_(2)O_(3) = " eq. of " K_(2)Cr_(2)O_(7)`
`m/(x+16) xx 5 + ((2.198 -m))/(2x+48) xx 8 = 0.015 xx 6 " "...(2)`
Solving eqns . (1) and (2) ,
x = `100.04`